Suppose I have a mesh containing, among other things, two cubes of different sizes, both oriented so that the main axes of these cubes are parallel to the world axes.
How can I align these cubes so that the top planes are at the same z coordinate, leaving other coordinates unchanged?
One way to do it is to separate these cubes into two different objects, and to align these, but the original object contains a lot more than the two cubes, so it needs to be reconstructed after the alignment, which is too much effort.